Only one time I got accused of being a creep because a girl didn't believe I didn't have a facebook and thought I was trying to cheat my nonexistent girlfriend. So having no facebook makes you a natural bullet dodger ;)

Most of the time if there are 'big' things I missed because I lack fb/sc/tw/insta I get updated in normal conversations, friends come sit with me and show some 'awesome' photo on their phone and we talk about it.

Like everything 'social media' takes up time and you're probably better off watching 2 TNG-Star trek episodes a day than spending on that. (Or read a book, listen to a podcast while walking outside or whatever hobby thingies you like).

Some answers to the 'why not?' question:

I wouldn't be active on it anyway, messaging me on that would result in me not reading it.

Any of these reasons https://saidit.net/s/Internet/search?q=facebook&sort=top&restrict_sr=on&t=all

And "I'm not comfortable with sharing that kind of information for the public".

Honesty works best.